Encapsulated spatial light modulator having large active area

Abstract

A die for spatial light modulation includes a substrate having a top surface having a length less than 15 mm and a width less than 11 mm, a spacer wall on the top surface of the substrate, a transparent encapsulation cover on the spacer wall, wherein the spacer wall and the encapsulation cover define a cavity over the substrate, a spatial light modulator on the substrate and within the cavity, and an opaque aperture layer on a surface of the encapsulation cover. The aperture layer includes an opening exposing the transparent window to allow the spatial light modulator to receive a light beam from outside of the cavity or send a light beam outside of the cavity. The spacer wall has a thickness equal to or less than 0.5 millimeters.

1 . A die for spatial light modulation, comprising:
 a substrate having a top surface having a length less than 15 mm and a width less than 11 mm;   a spacer wall on the top surface of the substrate;   a transparent encapsulation cover on the spacer wall, wherein the spacer wall and the encapsulation cover define a cavity over the substrate;   a spatial light modulator on the substrate and within the cavity; and   an opaque aperture layer on a surface of the encapsulation cover, wherein the aperture layer comprises an opening exposing the transparent window to allow the spatial light modulator to receive a light beam from outside of the cavity or send a light beam outside of the cavity, wherein the spacer wall has a thickness equal to or less than 0.5 millimeters.   
   
   
       2 . The die of  claim 1 , wherein the aperture layer is on a lower surface of the encapsulation cover and at least a portion of the aperture layer is inside the cavity. 
   
   
       3 . The die of  claim 1 , further comprising an electrode configured to send electric signals to or receive electric signals from the spatial light modulator, wherein the electrode is on a portion of the top surface of the substrate that is outside the cavity. 
   
   
       4 . The die of  claim 1 , wherein the spacer wall defines a cavity height between the substrate and the encapsulation cover, wherein the cavity height is between about 0.1 millimeters and about 1.0 millimeters. 
   
   
       5 . The die of  claim 1 , wherein a distance between the top surface of the substrate and a top surface of the encapsulation cover is between about 0.2 millimeters and about 2.0 millimeters. 
   
   
       6 . The die of  claim 1 , wherein a distance between a top surface of the encapsulation cover and a bottom surface of the substrate is 4 millimeters or less. 
   
   
       7 . The die of  claim 1 , further comprising an anti-reflective layer formed on a surface of the encapsulation cover. 
   
   
       8 . The die of  claim 7 , wherein at least a portion of the anti-reflective layer is between the lower surface of the encapsulation cover and the aperture layer. 
   
   
       9 . The die of  claim 1 , wherein the top surface of the substrate has a length less than 15 mm and a width less than 11 mm, wherein the substrate in each die includes a top surface and the opening in the aperture layer in the cavity in the die has an area equal to at least 60% of the top surface of the die. 
   
   
       10 . The die of  claim 1 , further comprising a light absorbing material on a surface defining the cavity, the light absorbing material configured to absorb light in the cavity. 
   
   
       11 . The die of  claim 10 , wherein the light absorbing material is on at least one of a surface of the spacer wall, a lower surface of an aperture layer on a lower surface of the encapsulation cover, or a top surface of the substrate in the cavity. 
   
   
       12 . The die of  claim 1 , further comprising a moisture absorbing material on a surface defining the cavity. 
   
   
       13 . The die of  claim 12 , wherein the aperture layer is on a lower surface of the encapsulation cover and the moisture absorbing material is on a surface of the aperture layer inside the cavity. 
   
   
       14 . The die of  claim 1 , wherein the spatial light modulator comprises an array of tiltable mirrors and the array is characterized by a first lateral dimension and a second lateral dimension, wherein the first lateral dimension of the array of tiltable mirrors is wider than a corresponding dimension of the opening in the aperture layer. 
   
   
       15 . The die of  claim 1 , wherein the spatial light modulator comprises a tiltable mirror configured to tilt to an on position to reflect an incident light through the opening and to tilt to an off position where reflected incident light is not directed through the opening. 
   
   
       16 . A die for spatial light modulation, comprising:
 a substrate having a top surface having a length less than 15 mm and a width less than 11 mm;   a spacer wall on the top surface of the substrate;   a transparent encapsulation cover on the spacer wall, wherein the spacer wall and the encapsulation cover define a cavity over the substrate;   a spatial light modulator on the substrate and within the cavity; and   an opaque aperture layer on a surface of the encapsulation cover, wherein the aperture layer comprises an opening exposing the transparent window to allow the spatial light modulator to receive a light beam from outside of the cavity or send a light beam outside of the cavity, wherein the opening in the aperture layer has a surface area equal to at least 60% of a surface area of the top surface of the substrate.   
   
   
       17 . A method for encapsulating a spatial light modulator, comprising:
 forming an opaque aperture layer having a plurality of openings on a transparent encapsulation cover;   forming spacer walls having a thickness equal to or less than 0.5 millimeters on a surface of the encapsulation cover;   connecting the spacer walls to a surface of a substrate having a plurality of spatial light modulators to form a plurality of cavities on the substrate with each cavity encapsulating at least one spatial light modulator, wherein the aperture layer in the cavity includes an opening that allows the spatial light modulator to receive a light beam from outside of the cavity or send a light beam outside of the cavity; and   cutting the substrate and the encapsulation cover to form a plurality of dies each including a spatial light modulator in a cavity, wherein the substrate in each die includes a top surface having a length less than 15 mm and a width less than 11 mm and the opening in the aperture layer in the cavity in the die has an area equal to at least 60% of the top surface of the die.   
   
   
       18 . The method of  claim 17 , wherein the spacer wall is formed on the aperture layer. 
   
   
       19 . The method of  claim 17 , further comprising forming an electrode on a portion of the top surface of the substrate outside the cavity, wherein the electrode is configured to send electric signals to or receive electric signals from the spatial light modulator. 
   
   
       20 . The method of  claim 17 , wherein the spacer wall defines a cavity height between the substrate and the encapsulation cover, wherein the cavity height is between about 0.1 millimeters and about 1.0 millimeters. 
   
   
       21 . The method of  claim 17 , wherein a distance between the top surface of the substrate and a top surface of the encapsulation cover is between about 0.2 millimeters and about 2.0 millimeters. 
   
   
       22 . The method of  claim 17 , wherein a distance between a top surface of the encapsulation cover and a bottom surface of the substrate is 4 millimeters or less. 
   
   
       23 . The method of  claim 17 , further comprising:
 forming an anti-reflective layer formed on a surface of the encapsulation cover;   disposing a light absorbing material on a surface to be enclosed in the cavity; and   disposing a moisture absorbing material on a surface to be enclosed in the cavity.   
   
   
       24 . The method of  claim 23 , wherein the light absorbing material is formed on a portion of the aperture layer that is inside the cavity. 
   
   
       25 . The method of  claim 23 , wherein the step of disposing a moisture absorbing material comprises:
 dispensing a fluid comprising the moisture absorbing material on the surface to be enclosed in the cavity; and   removing a solvent from the fluid dispensed on the surface to be enclosed in the cavity.